Caligus equulae Ho and Lin, 2003

Moon, S. - Y. & Kim, I. - H., 2012, Sea lice (Copepoda, Siphonostomatoida, Caligidae) new to Korea, including three new species, Journal of Species Research 1 (2), pp. 175-217 : 176-181

Caligus equulae Ho and Lin, 2003

( Figs. 3 , 4 )

Caligus equulae Ho and Lin, 2003a, p. 59 , figs. 3-5; Ho and Lin, 2004, p. 179, figs. 93-95.

Material examined. 1J from the skin of Carangoides equula (Temminck and Schelegel) , Jeonchon Port, Gampo-eup, Gyeongju-shi, in the eastern coast of Korea, S. Y. Moon, 2 February 2010 .

Male. Body ( Fig. 3A ) 1.80 mm long. Cephalothoracic shield circular, 1.01× 0.95 mm; lateral zone with T-shap- ed ventral rib, without posterolateral pit; posterior sinus deep. Genital complex fused with abdomen to form fusiform genitoabdomen ( Fig. 3B ) of 567×333 µm. Fourth pedigerous somite incompletely articulated from genitoabdomen. Caudal ramus 46×45 µm, almost as long as wide, with 4 pinnate and 2 small naked setae.

Antennule ( Fig. 3C ) 2-segmented; proximal segment about 132 µm long, with 27 pinnate and 2 naked setae; distal segment elongated, 135 µm long, slightly longer than proximal segment, with 12 naked setae and 2 aesthetascs. Antenna ( Fig. 3D ) 3-segmented; first segment with 2 adhesion pads; second segment narrowed distally, with subdistal and lateral adhesion pads; third segment forming strongly curved claw bearing 2 proximal setae. Postantennal process ( Fig. 3E ) proximally bearing 1 small posterior subsidiary process and 2 papillae each tipped with 2 or 3 setules; distal claw of postantennal process blunt and uneven; another papilla located posterior to postantennal process tipped with 3 setules.

Mandible with 12 teeth distally. Maxillule ( Fig. 3F ) consisting of anterior papilla bearing 3 unequal setae and posterior process bearing abhesion pad and 1 small seta. Maxilla ( Fig. 3G ) 2-segmented; proximal segment unarmed; slender distal segment with membrane (flabellum) at about 2/3 region of segment; calamus about twice as long as canna. Maxilliped ( Fig. 3H ) 3-segmented; first segment (corpus) robust, with strongly convex outer margin and 2 small processes on inner margin; second segment (shaft) short, distally with 1 seta and 1 small, digitiform seta; third segment as evenly curved claw. Sternal furca ( Fig. 3I ) with narrow, rather divergent tines.

Armature on rami of legs 1-4 as follows:

Leg 1: exopod 1-0; III,1,3; endopod (vestigial)

Leg 2: exopod I-1; I-1; II,I,5; endopod 0-1; 0-2; 6

Leg 3: exopod I-0; I-1; III,4; endopod 0-1; 6

Leg 4: exopod I-0; I-0; III; endopod (lacking)

Leg 1 ( Fig. 3J ) coxa with branched outer setule; basis with weakly pinnate outer seta, smaller pinnate inner seta, and patch of numerous minute spinules on ventral surface. Proximal exopodal segment with 1 small outer distal naked seta and row of spinules on inner margin; distal segment with three distal spines each accompanied by flabelliform membrane; two inner distal spines bifurcating at about their distal third; distal seta naked; endopod digitiform and tipped with 2 small processes. Leg 2 ( Fig. 4A ) coxa with large seta on inner posterior margin, 1 patch of minute spinules and 1 setule on ventral surface; basis with small outer seta and 1 inner setule and membrane on inner part of posterior margin; first endopodal with spinules on distal part of outer margin; outer side of basis and first exopodal segment with broad membrane (not illustrated in Fig. 4A ). Leg 3 ( Fig. 4B ) protopod (apron) with longitudinally elongate patch of spinules on mid-ventral surface and several flexible, irregular, papillae on inner ventral surface; spine on first exopodal segment enlarged and strongly curved. Leg 4 ( Fig. 4C ) protopod moderately expanded, with small outer distal seta and 4 small setules on outer side; exopodal segments similar in length; spines on these segments similar in shape, all with membrane on both sides. Leg 5 represent- ed by 1 and 3 small setae on lateral side of genitoabdomen. Leg 6 represented by 2 smalle setae on genital flap ( Fig. 3B ).

Female. Unknown in Korea.

Distribution and host. Known only from Carangoides eauula (Temminck and Schlegel) in Taiwan ( Ho and Lin, 2003a) and Korea (the present record).

Remarks. A single male specimen found in the present study agrees well with the original description by Ho and Lin (2003). The main characters shared by the specimens from both Taiwan and Korea are the possession of the small body size, the fusiform genitoabdomen, the small caudal rami, the elongate distal segment of the antennule, the simple terminal claw of the antenna, and the 3 small pinnate setae on the posterior (medial) margin of the distal exopodal segment of leg 1.

Figures

Fig. 3. Caligus equulae Nordmann, female. A. habitus, dorsal. B. urosome, dorsal. C. antennule. D. antenna. E. postantennal process. F. maxillule. G. maxilla. H. maxilliped. I. sternal furca. J. leg 1. Scales=A. 0.2 mm. B. 0.1 mm. C-J. 0.05 mm.

Fig. 4. Caligus equulae Nordmann, female. A. leg 2. B. leg 3. C. leg 4. Scales=0.05 mm for all.